The invention is based on a single-screw or multi-screw extruder having one or more intermeshing screw shanks surrounded by a barrel. Extruders of all types are described in detail, for example, in the book by H. Herrmann, Schneckenmaschinen in der Verfahrenstechnik (Extruders in processing), published by Springer-Verlag, Berlin/Heidelberg/New York, 1972.
In conventional extruders of steel and related metallic materials, high-viscosity media with abrasive or corrosive or aggressive phases cannot be processed. Limits are also set to the use of metallic materials at very high temperatures.
Furthermore, an extruder is described in the Swiss Pat. No. CH 445 457, the barrel and screw shank fittings of which consist of individual narrow blades arranged perpendicular to the axis and adhesively fixed or soldered to one another. However, due to this type of connection, such extruders are not suitable for the above-mentioned processes and applications.
The material properties of ceramic materials make them of increasing interest for apparatus and mechanical engineering. For problems with abrasive media there are already various solutions in which machine parts are lined with ceramic or provided with a ceramic layer by a special application method. Due to the different coefficients of thermal expansion of the corresponding material combinations, problems frequently occur regarding the service life of the combined metal-ceramic part.